As an improvement on these methods of transport, the plan was adopted of fixing rows of upright wooden posts, connecting floor and ceiling, on each side of a car as supports for two or three tiers of rough wooden bunks, a central gangway through the car being left. In this way the available space in the car was much better utilised than with the straw-on-floor system. Next, in place of the bunks, came an arrangement by which the stretchers whereon the patients lay could be securely lashed to the uprights; while this was followed, in turn, by the insertion of wooden pegs into the uprights and the placing on them of large and strong india-rubber rings into which the handles of the stretchers could readily be slipped, and so suspended. The first car so arranged came into use in March, 1863. Meanwhile the Philadelphia Railroad Company had, at the end of 1862, fitted up an ambulance car on the principle of a sleeping car, but so planned that the stretchers on which the sufferers lay could be made to slide in or out of the wooden supports. This particular car was capable of accommodating fifty-one patients, in addition to a seat at each end for an attendant. Other innovations introduced on the car were (1) a stove at which soups could be warmed or tea made; (2) a water tank, and (3) a locker. What the introducers of these improvements mainly prided themselves upon was the fact that the patient could remain, throughout the entire journey from field hospital to destination, on the stretcher he had been placed on at the start. The adoption of this principle necessitated, however, uniformity in the dimensions of the stretchers in order that these could always be accommodated on the ambulance-car fittings. The next important development was reached when the ambulance _car_, run in connection with ordinary trains, and used for exceptionally severe cases, was succeeded by the ambulance _train_. Here came further innovations, the nine or ten "ward-cars," of which such a train mainly consisted in the Eastern States, being supplemented by others fitted up as dispensary and store-room, kitchen, and quarters for surgeon, attendants, and staff of train, besides carrying all necessary appliances and provisions for the journey.